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. Author manuscript; available in PMC: 2012 Nov 1.
Published in final edited form as: Arterioscler Thromb Vasc Biol. 2011 Nov;31(11):2643–2652. doi: 10.1161/ATVBAHA.111.233189

Figure 3.

Figure 3

Angiopoietin-1 (Angpt-1) requires IQ domain GTPase-activating protein 1 (IQGAP1) to rescue acute mediator-induced endothelial permeability. A, Immunocytochemistry for VE-cadherin, actin, and 4,6-diamidino-2-phenylindole (DAPI) 72 hours after control or IQGAP1 small interfering RNA (siRNA) transfection. Cells were challenged for 15 minutes with thrombin (1 U/mL) (a and b) or coincubated with thrombin and Angpt-1 (300 ng/mL) (c and d). In control-silenced cells, Angpt-1 abolished the paracellular gaps (green arrows) but completely failed to do so if IQGAP1 was silenced (green dotted line) (representative of 3 experiments; scale bar 10 μm). B, Human microvascular endothelial cells (HMVECs) were transfected with control or IQGAP1 siRNA. After 72 hours, thrombin (1 U/mL)+Angpt-1 (300 ng/mL) or vehicle was applied. Angpt-1 was able to rescue thrombin-induced drop in TER only in the presence of IQGAP1 (n=2 per condition). C, Bar graph±SEM representing the change in normalized TER in response to thrombin for above conditions at the time of maximal response (n=4 per condition). TER normalization refers to the start point of the experiment for each condition (ie, 72 hours after siRNA transfection, when cells reached 100% confluence).